In DeNOx & DeSOx units, TECNOVA HT has already engineered, integrated and installed several Gas Analysis Systems dedicated to Process applications in:
- Power Generation units
- Steel Mills
- Cement Plant
- Chemical Plants
- Incineration units
A typical DeSOx unit is the Flue Gas Desulfurization: the purpose of FGD is to remove Sulphur Dioxide SO2 from exhaust flue gas. In fact, due to the presence of Sulphur both in coal and oil as standard fossil fuels to be burnt in the pow-gen, the presence of Oxygen causes the conversion into Sulphur Dioxide and the excess of O2 could also move the equilibrium to SO3.
NOx gases are usually produced as a reaction between nitrogen and oxygen during combustion in the air of fossil fuels: the SCR Selective Catalytic Reduction Unit removes this contaminant converting NOx in N2 and H2 O by a catalytic reaction with the aid of a gaseous reductant agent like urea or ammonia. This is the working principle of a DeNOx unit.
Why are DeNOx & DeSOx so important to mitigate the environmental impact? When Sulphur Dioxide SO2 and Nitrogen Dioxide NOx are emitted into the atmosphere they react with water and oxygen, thus forming Sulphuric and Nitric acids. Those acids are mixing with water droplets in the clouds before falling to the ground: this phenomenon is called Acid Rain. Acidification of soils, trees, rivers or seas is one of the critical environmental issues of the last two centuries.
Therefore the scope of TECNOVA HT Gas Analysis Systems installed in FDG or SCR units is:
- to assess the effectiveness of removal of pollutants
- to manage several process parameters
- to increase the conversion performances
- to minimize by-products
- to lower energy consumption
Easy?
First of all, the piping is very large in this kind of unit, with DN ranging from 6 to 12 meters. Therefore, the type and installation of any sampling probe is always customized and extensive technical knowledge is required in order to guarantee a reliable analysis. High temperature, huge dust load, unstable flow…for this specific application, TECNOVA HT has invented a new line of isokinetic probes able to manage all these challenging issues.
Therefore, TECNOVA HT is well aware that the process gas to be analysed on-site in those specific units could be very different from any technical data sheet or gas composition provided during the engineering stage: the presence of unknown interferers, a different flow rate, a massive load of dust, and higher temperature are only a few among the various parameters that could compromise performance of the best analysis system.
How to mitigate this situation? The first line of defence is the choice of good and reliable analysers: many times, poor integration starts from a poor analyser selected only because of its low cost. Since 1985, TECNOVA HT has been in a strong partnership with leading players in Gas Analysis such as FUJI Electric with NDIR or Zirconium Oxide principles: performance, accuracy, reliability are the features of each instrument integrated in our systems.
The second line of defence is the sampling and conditioning system, always engineered and assembled to fit with wrong gas composition, process upsets, presence of unknown interferers….with a conservative approach.
Third, TECNOVA HT relies on its Service Department to carry out commissioning and start-up procedures: thanks to our technicians’ renowned skills, any on-site modifications are done in a timely fashion, as well any re-engineering work needed to mitigate any non-conformity fulfilling the customer’s total satisfaction.
In DeNOx & DeSOx units TECNOVA HT is able to monitor both upstream and downstream streams to offer the best view of unit performance to the Field Operators: any system is at least a 2-channel type and even if the core analyzer is single, each channel is independent and engineered to avoid any memory effect. A downstream analysis could only monitor the result of pollutants removal but it will not help the unit management: infact a disproportionate injection of urea or ammonia will be really expensive not only for the cost of those chemicals but also the cost of ashes disposal while an inadequate one will not obviously clean up the gases.
So the choice of analytical ranges is driven by needed sensitivity, really different between upstream and downstream applications. More, special care is given to analyze the water carry-over to tune the interferences between water itself and reactants.
DeNOx & DeSOx Performance Management by TECNOVA HT will help you, your process unit and, more important, it will help your and our environment.
